1. Field of the Invention
This invention relates to network adaptors and more particularly relates to network adapter (latency) optimization by optimizing interrupt processing and reducing interrupt frequency.
2. Description of the Related Art
The IBM System z mainframe computer platform may use a specialized network adaptor called an Open Systems Adaptor (OSA). The OSA provides a means to virtualize and abstract the details of the actual hardware Network Interface Card (NIC). The host communicates with the OSA and OSA communicates with the NIC. A single OSA can simultaneously support hundreds of Operating Systems images, and thousands of host connections, and yet even more TCP/IP connections. The OSA provides many advantages, primarily in the area of sharing and virtualization. However, a down side is the latency created by this additional tier or layer that comprises the OSA. This latency is compounded by heavy volume of networking traffic and complicated by higher degrees of adapter sharing.
One main source of delay is the interrupts, or notifications to hardware or software, required for both inbound and outbound data traffic. The latency created by generating and reacting (processor utilization) to the interrupts is a significant delay. Some of this delay is actually within the host itself or the host bus. The frequency and overhead associated with managing interrupts related to very high data rates (1 Gbs or 10 Gbs links) for so many host connections is an issue related to latency through the OSA.